| 摘要 |
PURPOSE:To narrow a track pitch and to increase recording density by radiating a main beam and sub-beams to a recording/reproducing track and tracks on both the side of said track and finding out a difference between the reproduced signals of these beams. CONSTITUTION:A main beam 5 is radiated to a track 2 and sub-beams A, B are radiated to tracks 1, 3 in three adjacent tracks 1-3 from a diffraction grating or an array laser having three light emitting parts. At that time, signals on the tracks 1, 3 based upon two sub-beams A, B are reproduced and a difference between the reproduced signals of the sub-beams and that of the main beam 5 is found out. Since the reproducing time of the main beam and the sub-beams is different in accordance with a track speed and a beam position, a difference at the same time is found out by delaying the signals. Thereby, even if the track pitch is narrowed, crosstalk can be removed. Thus, the recording density can be sharply increased. |
